Horizontal windmill

ABSTRACT

Multiple radial beams extend horizontally for rotation about a vertical axis, and support at their outboard ends vertical, aerodynamic sails which pivot about vertical axes. Cams and cam followers pivot trim tabs at the downstream ends of the sails which shifts the main body of the sail to produce additive lift forces for sustained rotation in a desired direction, while weather cocking the sail as the arms move to right angle positions with respect to the wind.

United States Patent 11 1 1111 3,877,836 Tompkins Apr. 15, 1975HORIZONTAL WINDMILL 2,622,686 12/1952 Chevreau et al 416/23 [76]Inventor: Leo L. Tompkins, 127 Wacaster St., FOREIGN PATENTS ORAPPLICATIONS Jackson, MISS- 39209 1,056,550 4/1959 Germany 416/111 [22]FiledI Aug. 13, 1974 1,072,210 12/1959 Germany 416/111 PP N05 497,156Primary ExaminerEverette A. Powell, Jr.

Attorney, Agent, or FirmSughrue, Rothwell, Mion, 52 us. c1. 416/119;416/23; 416/111 Zmn and Macpeak [51] Int. Cl. F03d [58] Field of Search416/23, 111, 117-119, [57] ABSTRACT 416/132, 132 A, 139, 186 A Multipleradial beams extend horizontally for rotation about a vertical axis, andsupport at their outboard [56] References Clted ends vertical,aerodynamic sails which pivot about UNITED STATES PATENTS vertical axes.Cams and cam followers pivot trim tabs 233,226 10/1880 Forbes 416/111 atthe downstream ends of the sails which shifts the 1,556,012 lO/l925Flettner 416/23 main body of the sail to produce additive lift forcesfor 1,780,431 McCarroll ustained rotation in a desired direction1,973,290 9/1934 Leon 4l6/lll w ather ooking the ail as the arms move toright 2,044,794 6/1936 Klsevalter 416/118 angle iti n withrespect to thewind. 2,106,557 l/l938 Putnam 416/41 X 2,437,659 3/1948 Albers 416/23 X6 Claims, 6 Drawing Figures HORIZONTAL WINDMILL BACKGROUND OF THEINVENTION 1. FIELD OF THE INVENTION This invention relates to windmillsand more particularly to a windmill whose driving surfaces are fullycontrollable with respect to the wind direction.

2. DESCRIPTION OF THE PRIOR ART Most windmills in use during the pastcenturies have employed a horizontal rotational axis with the vanes ofthe windmill being radially disposed to that axis which requiresextensive horizontal support and results in force imbalance acting onthe rotary vane array.

SUMMARY OF THE INVENTION The present invention concerns the type ofwindmill which the sails are vertically oriented, are of aerodynamiccross section similar to the vertical stabilizers in airplane tailsections, and are mounted for pivoting about a vertical axis at theoutboard ends of respective beams which form a radial array, arecircumferentially spaced equally and are mounted for rotation about avertical axis at the beam intersection point. The improvement resides inautomatic means to set the angle of attack of the sails and to controlthe speed. Shut-off is accomplished by neutralizing the control surfacesand letting the sails weather cock or align themselves into the wind forminimum drag.

It is, therefore, a primary object of the invention to provide awindmill which fully controllable within a wide range of wind speed andhaving configuration involving a vertical output shaft so that anymachinery driven by the shaft may be placed out of the slipstream of thewind passing over the sails and protected from the weather.

A further object of the present invention is to provide a windmill thatis both economical to build and rugged in its resistance to theelements. This results in low initial and minimum maintenance costs, andprevents the windmill from being blown away or heavily damaged byperiodic storms which pass its way.

A further object of this invention is to provide sails to a windmillthat offer a minimum resistance to the winds along its path as comparedto the useful torque produced and sails which generate forces which areadded to each other and one wherein the forces being exerted by thesails through the respective cross arms to the central take-off shaftbalance out each other, do not overload the tower supporting the same,and permit each of the sails to provide additive torque for rotation ofthe shaft in a given direction.

A further object of this invention is to provide a windmill whose sailshave low resistance to the wind when it is shut down or running at lightload in a relatively high wind.

A further object of this invention is to provide a windmill of this typewhich has low inertia to accommodate changes both to alterations indirections of the wind and in velocity of the same, while exposing aslittle area as possible to the vertical components of wind gusts.

It is further object of the present invention to employ a design whichis esthetically appealing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of oneembodiment of the vertical sail, windmill of the present invention.

FIG. 2 is a top plan view of the windmill of FIG. 1.

FIG. 3a is a top plan view, partially in section, of a portion of onebeam of the windmill of FIG. 2 and the sail carried thereby, with thelower sail pointing toward the pivot axis of the windmill, with thecontrol arm in the high eccentric position relative to the sail supportshaft axis.

FIG. 3b is a similar view to that of FIG, 3a, with the cam shifted tothe low eccentric position.

FIG. 30 is a similar view to that of FIGS. 3a and 3b with the camshifted to full eccentric position opposite to that of FIG. 3a.

FIG. 4 is a side view of the windmill showing the actuating means forthe sail assemblies.

DESCRIPTION OF THE PREFERRED EMBODIMENT The windmill indicated generallyat 10 comprises, in one form, a tower 12 formed by four upwardly andinwardly inclined posts 14 which fixedly and commonly support at theirupper ends a collar assembly 16 which rotatably supports a vertical,power take-off shaft 18 which has coupled thereto at its upper end across arm mounting hub 20. Extending outwardly from the hub 20 are aplurality of horizontal beams 24, preferably, in even number, spacedequi-distantly in a circumferential direction with respect to each otherand rotating within a horizontal plane. The beams 24 rotate with the hub20 and with the power take-off shaft 18. At the outer end of each beam24, there is provided a vertical pivot shaft 26 which is fitted into aguide and thrust bearing (not shown) located in the beam, it beingnecessary for the shaft 26 to be free to rotate but being fixedvertically, that is, it may not move up and down with respect to beam24. The shafts 26 pivotably support sail assemblies 28a, 28b, 28c and28d on respective beams. For each sail assembly such as sail assembly28a, FIG. 4, there is provided an upper sail 30 and a lower sail 32which are fixed to the shaft 26 and both rotate with that shaft. Bothsails are aerodynamically configured, that is, they are streamlined andare shaped so as to provide aerodynamic lift depending upon their angleof attack with respect to the wind. In cross section, they are quitesimilar in configuration to that of a conventional aircraft wing. Thepivot shaft 26 supports the upper sail 30 and the lower sail 32 suchthat the center of lift of each sail 30 and 32 is slightly behind theshaft 26, relative to the direction from which the wind emanates. Withthe pivot axis slightly in front of the center of lift, the upper sail30 and lower sail 32 will naturally try to weather cock or alignthemselves with the wind at its minimum lift and drag angle.

With respect to the lower sail 32, this sail is provided with a trim tab34 coupled to the lower sail 32 by way of'a hinge joint, formed by ahinge pivot pin 36 at the trailing edge of the same, the trim tab 34acting to form a control surface, that is, a means for shifting the sailassembly about the pivot axis as defined by shaft 26 relative to thewind direction depending upon which side of the longitudinal axis of thesail assembly, the trim tab 34 is displaced.

By further reference to FIG. 2, the improvement provided by the windmillof the present invention resides in the means for automaticallydisplacing the trim tabs 34 of respective sail assemblies 28a, 28b, 28cand 28d as the sail assemblies cause beams 24 to rotate in unison aboutthe pivot axis as defined by power take-off shaft 18. As is seen byarrow 38, continuous counterclockwise rotation occurs by controlling theposition of the trim tabs 34. When the beams 24 are generally inalignment with the wind indicated by the three arrows 40, the sails andthe trim tabs of those sail assemblies are moved to non-alignedpositions, while when the beams 24 are generally at right angles to thedirection of the wind, those sail assemblies are permitted to weathercock, that is, to move to a position of alignment with the wind. Thus,when the trim tab 34 is pivoted to the right of the'longitudinal axis ofdownwind sail assembly 280, the trim tab 34 develops a trim lift to theleft indicated by arrow 42, this shifts the trailing edge of the sail tothe left and air flow over the main body of the sail which is ofaerodynamic configuration, now produces a much larger lift 44 of thesail assembly 28c to right and tends to rotate the beam to the right orcounterclockwise about the pivot axis of shaft 18 as viewed from aboveas identified by arrows 38. With respect to sail assembly 28d, since itsbeam 24 is at right angles to the direction of the wind, the sailassembly 28d at the outer end of that arm is permitted to remain inneutral or to weather cock into the Wind and produce minimum drag, sincethey are at zero advantage with respect to the driving of the windmill.Further, as indicated in FIG. 2, the upwind sail assembly 28a has itstrim tab 34 pivoted to the left, producing a trim lift to the right asindicated by arrow 46, the upper and lower sails 30 and 32 pivot suchthat the trailing edge of the sail moves to the right and the leadingedge to the left and the air flow over the main body of the sailassembly produces much larger lift to the left as indicated by arrow 48tending also to rotate its support beam 24 counterclockwise about thepivot axis of shaft 18. Thus, the driving force exerted by the wind onsail as sembly 28a is additive to that force produced on sail assembly28c. Meanwhile, at this point in the cycle, the sail assembly 28bweather cocks in the identical man ner to sail assembly 28d for minimumdrag.

This type ofinteraction with the wind results in a very high torquebeing produced as compared to the drag and weight which would load thesupports in compari son to the windmill of the known prior art.

The trim tabs 34 are automatically controlled in response to the angularposition of the arms supporting the respective sail assemblies asderived from a cam and follower arrangement associated with the beams 24and thier sail assemblies. Reference to FIG. 3a, 3b and FIG. 4illustrate the make-up of the control mechanism and its nature ofoperation. For each sail assembly, a circular cam 50 is provided with anelongated slot or hole 52, through which passes the pivot shaft 26 ofthe sail assembly which of course is pivotably mounted to the outer endof a given beam 24. The circular cam 50 may be conveniently mountedbetween the beam 24 and the lower sail 32 as shown in FIG. 4 and thehole 52 is elongated in the direction of the longitudinal axis of thebeam 24 such that the circular cam 50 shifts longitudinally relative tothe axis of the beam 24 under control of a cam shift control rod 54. Thecontrol rod 54, in each case, is pivotably coupled to the cam 50 andextends radially inwardly toward the hub 20. The outer end of thecontrol rod 54 is pivoted at 56 to the upper face of the circular cam50. The inner end of the con trol rod 54 is pivotably coupled to one endof connecting rod 60 at 58 and the control rod 54 is spring biased bycoilspring 62 having one end fixed to the pivot connection betweenconnecting rod 60 and the inner end. of rod 54 and the other end securedby way of mount-.

ing screw 64 to the reduced diameter portion 66 of hub 20. A camfollower 68 in the form of an oblong circle. having a minor internaldiameter equal to the diameter clamps 72 mounted to the upper face 74 ofthe lower sail 32. The connecting rod terminates in a laterally offsetportion 76 which is pin coupled to bell crank 78.

by way of a pivot pin 80. The inner end of the bell crank 78 is fixed totrim tab 34 at a right angle to the major axis of said trim tab at apoint near to the pivot pin 36, such that axial shifting of theconnecting rod 70 affects shifting of the trim tab 34 from a position tothe left of the longitudinal axis as seen from the trailing end of sailassembly, FIG. 3a; through a position where the trim tab 34 is in axialalignment with the sails 30 and 32, as when the effective cam surfacesare at equal distances from the center of shaft 26, and as shown in FIG.R

3b; to the position as shown in FIG. 30 when the connection rod 70 is atits most outward position and the sail is pointed away from the centerof the rotating assembly. The shifting of cam 50 relative to the shaft26 such that the shaft 26 occupies the proximate end of the elongatedhole 52 rather than the distal end, causes cam follower 68 to shiftalong with the connecting rod 70 in longitudinal direction, to aposition whereits cam surfaces are concentric with shaft 26 and the trimtab 34 will be in neutral position with respect to the sail 32 at allpositions of the sail with respect to the supporting beam 29. It isimportant only to realize that the cam 50 may be shifted with respect toshaft 26 such that the cam occupies a position coaxial therewith withthe shaft centered within the elongated slot 52, or position in whichthe shaft is either at the proximate or distal end of the slot or holewith respect to the pivot axis at.

the center of the windmill.

The mechanism for achieving shifting of rods 54 comprises upright pins84 which are fixed at their bottom ends to lower axially movable collar86 slidably po-' sitioned on hub 20. The pins 84 pass through openingsof slightly larger diameter within an upper fixed collar. 88. The pins84 are pivotably coupled to respective connecting rods 60 at pivot pinconnection 90. Thus, by shifting collar 86 axially with respect tocollar 88, the rods 54 are moved outwardly against the bias of springs62 or moved inwradly to shift the cams and force the cam followers tofollow to pivot the trim tabs to the desired position. Once the controlrods 54 are set, the trim tabs 34 will take the desired positionautomatically as the hub rotates, that is, the cams by be set such thatthe trim tab 34 of a given sail assembly is inclined to the right as thesail is in its downward position as is sail assembly 28c, and in generalalignment with the direction of the wind. The opposite is true when asail assembly occupies the position of sail assembly 28a in its fullupwind position and in general alignment therewith.

Since the sails pivot along with vertical shaft 26 as the beams rotate,the cam follower rotates about the cam 50. When the beams reachpositions generally transverse to the axis of the wind, the major axisof the cam permits the bell crank to move such that the trim tabs 34occupy in line or feathered position with the wind moving along bothsides of the sail assembly, the trim tabs 34 are at neutral positionsand the sail assemblies weather cock. It may be seen that axiallysliding or moving collar 86 up or down relative to fixed collar 88causes identical shifting axially of control rods 54 and equalpositioning of the cams 50 relative to their shafts 26 passingtherethrough.

To summarize, with the control rods 54 preset, such that the cam is atits radially inboard position with reference to the cam follower 68, thespring 62 pulls the connecting rod 70 in on the cam and working throughthe bell crank 78 will displace the trim tab 34 to the right of thelongitudinal axis looking in the direction of the wind. However, thissame sail assembly, when in the upwind position, will be facing radiallyoutward on its beam 24 corresponding to the position of sail assembly28a, and the cam follower 68 will be on the high part of the cam 50 andwill displace the trim tab 34 to the left as is required for cumulativecounterclockwise rotation. By putting the bell cranks 70 on the otherside of the beam axis, the action of the cam and cam follower and theconnecting rods 70 would effect reverse rotation to the trim tabs forthe sail assemblies at upwind and downwind positions and reverse thedirection of rotation of the windmill,

The sails to the left and the right of the wind are aligned across thebeam having their cam followers at the normal height of the cam and thetrim tabs will automatically move to neutral position.

The cams 50 and the operating rods 70 are made of heavy material and therotation of the beams 24 produce centrifugal forces tending to stretchthe springs 62, allowing the earns 50 to move towards their mostconcentric position relative shaft 26, that is, the shaft will becentered relative to the elongated hole with the cam follower followingthe movement of the cam. In the concentric position, the trim tabs 34are at neutral at all positions around the shaft and the windmill willbe shut off. When this action results from centrifugal force acting onthe springs 62, the windmill may not be completely shut off, but willreducce its speed to that which will produce the torque necessary tosustain a relatively constant speed. Thus, the present invention usesthe springs 62 to control the shifting of the control rod and theposition of the cams 50 relative to the shafts 26 passing therethroughto insure reduction in effort and a limit on the speed to compensate forchanges in the force of the wind over a wide range of wind conditions.

Additionally, the windmill may be shut down by outside action eithermanually, by means of the movement of collar 86 with respect to collar88 as shown by arrow 100 or by automatic controls (not shown). Shutoffcollar 86 in FIG. 4 is moved upward by any convenient means as by manualforce application, forcing the pins 84 to shift upward and movingconnecting rods 60 and moving in turn the operating rods 54 to shift thecams to their neutral position such that the trim tabs are positioned inalignment with the sails 30 and 32 of each sail assembly. With the sailsweather cocking, no torque is produced and minimum drag is experiencedby the windmill, thus preventing damage to the windmill in thecase ofstorms with their resultant high velocity winds.

While the invention has been particularly shown and described withreference to a preferred embodiment therof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

What is claimed is:

1. In combination; a windmill comprising;

a plurality of vertical aerodynamic sail assemblies,

sail supporting means for maintaining said sail assemblies in positionsfor pivoting about a vertical pivot axis for each assembly with thecenter of lift of each sail being slightly behind the vertical pivotaxis thereof and including at least one vertical aerodynamic sail ineach assembly,

means permitting said sail assemblies to move in a closed circular path,

means for additively applying the torque output of the wind acting onthe sails of said sail assemblies to provide output torque for saidwindmill,

a trim tab pivotably mounted to said at least one sail of each sailassembly such that the trim tab is disposed downwind from the trailingedge of said one sail,

control means responsive to movement of said sail assemblies about saidclosed circle for automatically pivoting said trim tabs to inclinedpositions relative to the longitudinal axis of the sails when said sailsupporting means is rotated such that the sail axis, the circular pathaxis and the wind direction are substantially in line such that thesesails provide additive forces tending to rotate said sail supportingmeans in the same direction, and for maintaining the sail assembliesthat are generally at right angles to the circular path axis and thewind direction in weather cocked position;

whereby, said sail assemblies provide minimum drag in comparison withtheir useful additive torque output.

2. The windmill as claimed in claim 1, wherein said support meanscomprises a vertically supported hub mounted for rotation about itsaxis, said plurality of sail assemblies are mounted at circumferentiallyspaced positions radially outward from said hub.

3. The windmill as claimed in claim 2, wherein said trim tab controlmeans comprises a cam operatively carried by said sail supporting meansat each sail assembly position and a cam follower carried by each sailassembly, operatively positioned with respect to said cam andoperatively coupled to said trim tab, such that upon rotation of saidhub and said sail supporting means, said sail assemblies pivot tomaintain positions in general alignment with the wind, and said camfollowers in following the profile of the cam pivot said trim tabs togiven inclined positions relative to the longitudinal axis of the sailassemblies when the sail assembly pivot and the hub of the sailsupporting means are generally in line with the wind.

4. The windmill as claimed in claim 3, wherein; each cam is circular andincludes an elongated slot intersecting its center, said sail ispivotably mounted to said sail supporting means by means of a shaftpassing through the elongated slot and said windmill includes meanscarried by said sail supporting means for maintaining the elongationparallel to the radius of said support such that the rotation of saidhub causes said cam follower to rotate about the sail pivot shaft suchthat said cam is eccentric to said cam follower when said sail axis, thehub axis and the wind direction are generally in line, with the sailassembly in a extreme downwind or extreme upwind position.

5. The windmill as claimed in claim 4, wherein said means for preventingrotation of said cam comprises a control rod mounted at one end to saidcam parallel to the elongated hole within said cam, and extendingradially inwardly from said cam towards said hub, and a biasing meansyielding holding said control rod and said cam toward the radiallyproximate end of said elongated slot, and said biasing means allowingsaid control rod to yield to centrifugal force to limit the upper speedof the windmill to a given value.

6. The windmill as claimed in claim 5, further comprising: an uppercollar fixed to said hub and rotatable therewith, a lower collarcoaxially mounted beneath 1 said upper collar on said hub and axiallyslidable toward and away from said uppercollar, holes carried atcircumferentially spaced positions within said upper collarcorresponding to said control rods, pins fixed to and extending upwardlyfrom said lower collar at circumferentially spaced positionscorresponding to said holes, and received by the holes within said uppercol lar and connecting rods pivoted at one end to the ends: of said pinsprojecting through said upper collar, and to a tric with or eccentric tothe sail pivot shafts.

1. In combination; a windmill comprising; a plurality of verticalaerodynamic sail assemblies, sail supporting means for maintaining saidsail assemblies in positions for pivoting about a vertical pivot axisfor each assembly with the center of lift of each sail being slightlybehind the vertical pivot axis thereof and including at least onevertical aerodynamic sail in each assembly, means permitting said sailassemblies to move in a closed circular path, means for additivelyapplying the torque output of the wind acting on the sails of said sailassemblies to provide output torque for said windmill, a trim tabpivotably mounted to said at least one sail of each sail assembly suchthat the trim tab is disposed downwind from the trailing edge of saidone sail, control means responsive to movement of said sail assembliesabout said closed circle for automatically pivoting said trim tabs toinclined positIons relative to the longitudinal axis of the sails whensaid sail supporting means is rotated such that the sail axis, thecircular path axis and the wind direction are substantially in line suchthat these sails provide additive forces tending to rotate said sailsupporting means in the same direction, and for maintaining the sailassemblies that are generally at right angles to the circular path axisand the wind direction in weather cocked position; whereby, said sailassemblies provide minimum drag in comparison with their useful additivetorque output.
 2. The windmill as claimed in claim 1, wherein saidsupport means comprises a vertically supported hub mounted for rotationabout its axis, said plurality of sail assemblies are mounted atcircumferentially spaced positions radially outward from said hub. 3.The windmill as claimed in claim 2, wherein said trim tab control meanscomprises a cam operatively carried by said sail supporting means ateach sail assembly position and a cam follower carried by each sailassembly, operatively positioned with respect to said cam andoperatively coupled to said trim tab, such that upon rotation of saidhub and said sail supporting means, said sail assemblies pivot tomaintain positions in general alignment with the wind, and said camfollowers in following the profile of the cam pivot said trim tabs togiven inclined positions relative to the longitudinal axis of the sailassemblies when the sail assembly pivot and the hub of the sailsupporting means are generally in line with the wind.
 4. The windmill asclaimed in claim 3, wherein; each cam is circular and includes anelongated slot intersecting its center, said sail is pivotably mountedto said sail supporting means by means of a shaft passing through theelongated slot and said windmill includes means carried by said sailsupporting means for maintaining the elongation parallel to the radiusof said support such that the rotation of said hub causes said camfollower to rotate about the sail pivot shaft such that said cam iseccentric to said cam follower when said sail axis, the hub axis and thewind direction are generally in line, with the sail assembly in aextreme downwind or extreme upwind position.
 5. The windmill as claimedin claim 4, wherein said means for preventing rotation of said camcomprises a control rod mounted at one end to said cam parallel to theelongated hole within said cam, and extending radially inwardly fromsaid cam towards said hub, and a biasing means yielding holding saidcontrol rod and said cam toward the radially proximate end of saidelongated slot, and said biasing means allowing said control rod toyield to centrifugal force to limit the upper speed of the windmill to agiven value.
 6. The windmill as claimed in claim 5, further comprising:an upper collar fixed to said hub and rotatable therewith, a lowercollar coaxially mounted beneath said upper collar on said hub andaxially slidable toward and away from said upper collar, holes carriedat circumferentially spaced positions within said upper collarcorresponding to said control rods, pins fixed to and extending upwardlyfrom said lower collar at circumferentially spaced positionscorresponding to said holes, and received by the holes within said uppercollar and connecting rods pivoted at one end to the ends of said pinsprojecting through said upper collar, and to the inboard ends of saidcontrol rod; whereby, axial shifting of said lower collar with respectto said upper collar shifts the cams relative to the sail pivot shaftsto position the cams concentric to position either concentric with oreccentric to the sail pivot shafts.